In IG.GFX, a Material Category is an important concept for efficient re-configuration of objects. While the Material of a geometry may change during run-time, it's Category is fix. Material Categories have a (scoped) Name, a Description and an optional Default Material.

An Implicit Material Category is a Material Category that is derived from a Material. Implicit Material Categories have been created to prevent the definition of Material Categories for fix Material assignments. By convention, the name of an Implicit Material Category is prefix @ plus the name of the Material, e.g. @IG.Mat.Red.